The effects upon the academic achievement of the situational stress, item difficulty information, and level of test anxiety were investigated. Subjects of the study consisted of 12 classes (720 students) of the sixth graders in the Namsan Primary School, located in Daegu. Classes were randomly assigned to the treatment conditions. The study employed the experimental design of Test anxiety (3) x Situational stress (2) x Item difficulty information(2), which is a completely randomized factorial. The Worry-Emotionality Questionnaire of Morris and Liebert, with a 5-point scale, was used to measure the anxiety level. Subjects were classified into three categories of low, medium, and high anxiety levels with the criteria score of 10 or less, 11-15, and 16 or above, out of a possible score range of 5-25. The situational stress was manipulated by creating a psychological threat through testing instruction, which resulted in a stressful vs. neutral test-taking situation. The item difficulty variable had two levels: one was given the item difficulty index as well as its verbal description and the other was given none of these. The academic achievement test had thirty-three multiple-choice items, each with four choices, covering the content area of first-semester part of the sixth grade arithmetic course. The following conclusions were drawn from the analysis of the data obtained: (1) The performance level of the high anxiety group was significantly lower when compared to the counterparts of the low or medium group. (2) When taking a test in a psychologically demanding and threatening situation, the subjects performed significantly lower. This negative effect was negligible for the low and medium anxiety group; however, it had a critical detrimental effect on the highly anxious students. (3) Providing the test-taking, students with the information of the test item difficulty had a negative effect on their achievement performance level. This negative effect was especially true when students were required to take the test in the demanding and stressful situation. But, providing the test item difficulty information did not interact with the test anxiety levels.